So yesterday I talked about things going wrong with my fruit trees. And these things are going to be problems as long as I don't spray insecticides and fungicides. So where are all the good guys in all this?
The added benefit of having ants treating the tree as one giant food source is many of them are predators of caterpillars. Especially small ones that they can manage. Mostly though they have a harassing nature to other bugs and ants, especially if the other bug is to big for them to handle. Even so, a healthy colony can over take or limit where the pest insects are able to go on the tree. And at their best the ants are killing the insects or forcing them to jump ship and find another host plant.
For images of ladybugs see BugGuide.net.
Before buying an invasive species of lady bugs, consider seeing if the aphids are a problem in the first place. If it's something you can just take a wet rag to and remove yourself why use the money? The lady bug they're selling in stores is invasive and bound to show up on it's own anyhow. Bottom line, if you have aphids you should try and encourage beneficial insects to keep them under control.